A hot process area inside the plant has a pair of exhaust fans for removing waste heat. Occasionally, a fan fails and soon operators are uncomfortable.
Earlier today, a fan began squeaking. The maintenance supervisor assigned Bob, a maintenance electrician, to “fix that squeak before that fan motor burns up.” Before heading to the roof, Bob grabbed a grease gun and a can of silicone spray.
Bob observed the belt and thought it too wobbly. He opened the local dis